Synchronizer



SYNCHRNIZER Filed oct. so, 1941 ATTORNEYS.

panying drawing illustrating one .gine

Patented May 1.8, 1943 Otto- E. Fishburn,

lChrysler Corporation,

corporation of Delaware Detroit, Mich., assigner to Highland Park,Mich., a

` Application October 30, 1941, Serial No. 417,090

' 13 Claims.

This invention relates to synchronizers and more particularly toimprovements in motor vehicle transmissions embodying engageable partssubject to clash-engagement.

One object of my invention is to' provide means for synchronizingengageable transmission parts which do not lend Another object is tosynchronize engageable transmission elements by bringing 4one of theelements to the speed of the other prior to their engagement, especiallywhere such elements are ordinarily engaged at a time whenthe speed ofone is zero and where the.other element is sub- 4vided for speed ratiochanges other than a drive ratio used to propel the vehicle fromstandstill.

Because of the inertia of the transmission parts, clutch drag or spin,or other factors, clashing of the engageable parts frequently results,my inziention being adapted to overcome such'objecons.

A further object is to provide means for synchronizing engaging gears ofa reverse drive gear set.

Further objects. and advantages of my invention will be more apparent asthis specification progresses, reference being made to the accom-.embodiment thereof and in which:

Fig. 1 is a longitudinal sectional elevational view-through mytransmission.

Fig. 2 is a transverse sectional view taken as indicated by line 2-2 ofFig. 1.

Fig. 3 is a fragmentary sectional view taken as indicatedvby line li-3of Fig. 2.

themselves to conventional methods of synchronization.

Fig. 4 is a similar view taken as indicated by i line 4-4 of Fig. 2.

In order to illustrate the principles of my invention I have shown thesame in connection with ing ratio-reverse in this instance.

The illustrated transmission comprises an endrive shaft III carrying thevaned impelier II of fluid coupling A. The impeller drives the vanedrunner I2 by fluid circulation in known manner, this runner drivingshaft I3 to which is driven clutch member mission input' shaft I]carrying the main drive pinion I8 in 'nected to shaft lowing the gear-of gear 24 or with teeth 21 of shaft I0 through coupling vshaft I1,thence through pinion through overrunning clutch D to gear 20, thencefixed the driving runner I4 of a conventional friction clutch B havingrelease levers l5. The

I6 is splined to the transl transmission C.

The transmission may b e of any desired type. that illustrated being ingeneral the transmission used on 1941 Chrysler fluid drive modied toincorporate ,myinventiom This transmission comprises countershaftgearing'drivingly con- I1. This gearing embodies va countershaft clusterhaving gears I9, 20, 2i driven through overrunning clutch D by a gear 22in constant mesh with pinion I8, the clutch D al- 22 to run slower butnot faster than gears I9, 20 and 2l. vTwo gears 23, 24 are mounted looseon the transmission output shaft 25 and are respectively in constantmesh .with gears I9 and 20. A shiftable clutch sleeve .I2I, which is inconstant drive connection with shaft 25, is adapted to selectivelyclutch with teeth 26 gear23 to respectively provide either flrst orthird speed over-l running drives. The rst speed drive is from A andclutch B to I8 and gear 22 to gear 24, teeth 26 and sleeve I2I to shaft25. The third speed drive is the same as first to clutch D whence thisdrive passes to gear I9 and gear 23, thence through teeth .21 and sleeveI2I to driven shaft 25. Blocker synchronizing rings 28 of commercialtype are operably associated with sleeve I2I to insure non-clash shiftof the sleeve.

A-second clutch sleeve 29 is splined on a forward extension of gear 23and is adapted to shift forwardly to clutch with teeth 30 of pinion I8to step-up the drive from iirst to second or from thirdto direct fourth.A blocker ring 3l prevents clutching of sleeve 29 with teeth 30 untilthe speeds of these parts are substantially the same at a time whenunder accommodation of clutch D. Second drive passes from shaft I1through sleeve 29 to gear 23, thence through gears I9,'20, 24 to teeth25 andy through sleeve I2I tofshaft 25.- Direct drive is'- from shaft I1directly through sleeve 29' to gear thence through teeth 21 and sleeve'I2 I to shaft 25. Clutch D overruns during the drives in third andfourth.

The primary function of clutch B is to accommodate release of shaft I1from runner I2 so as to facilitate shift of sleeve I2I between teeth 25and 2 1. Shift of sleeve 291s controlled autoshaft I1 is coasting downvi Y my invention,

matically by means well known and therefore not illustrated in mydrawing.

In order to drive 'the vehicle in reverse, a

driven gear 32 is mounted fixed on shaft 25 and adapted to be engaged byrearward shift of a reverse idler gear 33 by its shift yoke 36. The gear2| is the countershaft drive gear for the reverse gear 33 is in constantmesh with gear 2|.

The idler gear 33 is slidably mounted on a shaft 33 which isnon-rotatably supported by the transmission housing. 'I'his shaft has anannular detent 35 engaged, prior to shift of gear 33 toward gear 32,with a plurality of ball poppets 36 each yieldingly urged inwardly by aspring 3l seated outwardly by a disc 38 which in turn is seated bypeening inwardly the upper edge portions of a cylindrical opening 39 inthe synchronizer member 40. This member has a conical friction surface4| which enters a recess 32 formed in the rear face of hub 32B of gear33, this recess having a conical friction cup surface 33 lying closelyadjacent surface 4|. If'desired, surface 3| may be formed as a finelythreaded surface of approx-,- imately 40 threads per inch according tomy co. pending application Serial'No. 180,840, led December 20, 1937. I

Gear 33 has its hub 42a formed with a radial annular shoulder M radiallywithin surface t3 vand the entrant portion of synchronizer d@ isundercut with a groove 45 to receive a split snapring d6 of thecontracting type. The ring d3 isv expanded in assembling synchronizerdi! on shoulder llt. Then the synchronize: is pushed the disengagedclutch B whereby shaft Il drives shaft il even with clutch B disengaged.

By reason of my invention the aforesaid diniculties are overcome andgear 33 is synchronized with gear 32 as an incident to shifting gear 32rearwardly for reverse. At this time the gear 32 is not rotating becausedrivenshaft 23 is stationary, the vehicle being at rest. My synchronizerapplies a braking force to gear 33 before it engages gear 32 therebybraking the countersha cluster and drive shaft l? as follows.

The initial rearward shift of gear 33 brings friction surface 33 againstsurface 3| of the synchronizer d@ which is yieldingly held againstrearward movement on shaft 33 by the balls 36. Inasmuch as synchronizer3u cannot rotate, a braking force is applied to gear 33 of an" amountpredetermined by the action of balls 36 in detent 36. Further rearwardmovement of gear 33, after effecting the stopping of rotation of gear 33and parts connected thereto, causes balls 36 to spring inwardly and gear33 then engages gear 32 without clash, the synchronlzer ld movingrearwardly on shaft 3d along with gear 33. -The complete rearward shiftof gear 33 is practically continuous and operates to rapidly brake gear2| during. the rearward shift of gear 33 prior to its engagement withgear 32.

When returning gear 33 to its Fig. 1 neutral position, shoulder deacting on ring d6 restores the synchronizer d@ to itsFig. 3 position.

As a feature of my invention, when used with a fluid coupling A, it isnot necessary to manually releasel the clutch B in shifting to reversepro: vided that the synchronizing mechanism is made sumciently ruggedespecially with reference to the detent pressure in relation to thelocation from center and areas of the engageable synchronizingrearwardly until ring 66 contracts to lie behind shoulder 44 and thushold synchronizer du and gear 33 together as in Fig. 3 with surface d3slightly spaced from surface t l. In order to disassemble these parts inservice, the synchronizer 40 is provided with a plurality of registeredpairs of axially extending apertures di, 38 (Fig. 4) through which asuitable Ytool E is inserted to expand ring 46 sufficiently to permitthe synchronizer to leave gear 33. Synchronizer 40, at one or morepoints between balls 36, hasv splined connection at 39 with shaft' 34such that the synchronizer may slide rearwardly on the shaft but is ingon the shaft.

When itis desired to drive the vehicle in re` verse, the vehicle is ofcourse brought to a standstill and sleeves 29 and |2| in their Fig. 1neutral positions. Then'clutch B is disengagedand gear 33 shiftedArearwardly to mesh with gear 32 and then clutch B is engaged to effectthe reverse drive which is the same as first to clutch D vwhence thedsrive passes through gears 2 33 and 32 to shaft 2 When clutch B isreleased preparatory to shiftprevented from turn-v means, in shiftingthe transmission friction surfaces so as to suniciently retard therotation of all parts between runner i2 and the reverse idler gear 33 toprevent gear clash when* the latter is shifted for the reverse drive.

1. In a transmission having axially aligned driving and driven shafts;driving and driven gears, said driving gear being shiftable into and outof engagement with said driven gear, said driven gear being mounted onand having a confl stant drive connection with the driven shaft",countershaft gearing, including a countersha'it reverse gear, drivinglyconnected with the driving;

shaft; shift means operable to shift 'said driviii g i gear toward and.from engagement with driven gear thereby to provide a reversedri'yefrom said driving shaft to said driven sha-it through said countershaftreverse gear and safgi driving and driven gears; and means operablelu-Iresponse to gear-engaging operation of said shift; from neu' l toreverse, for braking rotation of said count@ Y'shaft reverse gear priortov engagement of driving and driven gears.

ing gear 33 into reverse, the inertia of the parts including shaft Il,the countershaft cluster, and

parts connected theretotends to keep gear 2| and idler 33 rotating *sothat gear 33 clashes, but for with gear 32. tThis is not onlyobjectionable in delaying the shift but is noisy and destructive of thegear teeth. The tendency `toward -rotation of gears 2| and 33 is furtheroften aggravated by. drag engagement through 75 2. In a transmissionhaving axially align'gyl driving and d'riven shafts; driving and driven4gears, said driving gear being shiftable into and' out; of engagementwith said driven gear, said driven gear being mounted on and having a.constant drive connection with the driven shaft; countershaft gearing,including a reverse gear, drivingly vc onnectedwith the driving shaft;shift means operable to shift said drivinggear toward' and fromvengagement with said ven gear thereby to provide a reverse drive fromsaid driving shaftto said driven -shaft through said countershaftreverse gear' and said countershaft said driving and driven gears.

" to said idler shaft and l providing an tershaft reverse gear priortoengagement of said.

driving and driven gears as an incident to operation of said shift meansto effect engagement of 3. In a transmission according driving gearhaving constant mesh with said countershaft reverse gear.

4. In a transmission having axially aligned ,driving and driven shafts;a driven gear mounted on said driven shaft; countershaft gearingdrivingiy connected to said driving shaft and com prising a countershaftreverse gear; av reverse idler gear having constant mesh with saidcountoclaim l; said tershaft reverse gear and adapted to be shifted intoand out of engagement with said driven gear; shift means for shiftingsaid reverse idler gear; and means operable in response to gearengagingoperation ofsaid shift means, when the transmission is manipulatedbetween neutral and reverse, for braking rotation of said countershaftreverse gear prior to engagement of said reverse' idler gear with saiddriven gear.

5. In a transmission having driving and driven shafts; a driven gearmounted on said driven shaft; countershaft gearing drivinglyconnected tosaid' driving shaft and comprising a countershaft reverse gear; areverse idler gear having constant mesh with said countershaft reversegear and adapted to be shifted into and out of engagement with saiddriven gear; shift means for shifting said reverse idler gear; a firstfriction surface having a constant axially aligned 6.v In a transmissionhaving axially aligned driving and driven shafts; a driven gear mountedon said driven shaft; countershaft gearing drivdrive connection withsaid reverse idler gear; a secondy with said' 8. In -a. transmissionhaving axially aligned driving and driven shafts; a driven gear mountedon said driven shaft; countershaft gearing drivingly connected to saiddriving shaft and comprising a countershaft reverse gear; a reverseidler gear having constant mesh with said countershaft reverse, gear andadapted to be shifted into and out 'of engagement with said driven gear;shift means for shifting said reverse idler gear; a stationarily mountedidler shaft support- I gear for shifting movement therealong; a frictionbraking surface disposed in the path of gear-engaging shift of saidreverse idler gear; and poppet meansproviding a yield- `ing connectionbetween said braking surface and said-idler shaft.

9. In a transmission having axially aligned driving and driven shafts; adriven gear mounted on said driven shaft: countershaft gearing drivinglyconnected to said driving shaft and coinprising' a countershaft reversegear; a reverse idler gear having constant mesh with said countershaftreverse gear and adapted to be shifted into and out of engagement withsaid driven gear; shift means for shifting said reverse idler gear; astationarily mounted idler shaft supporting said reverse idler gear yforshifting movement therealong; said reverse idler gear'having a recess ina side face thereof formed with a conical boundingly connected to saiddriving shaft and` com piising a countershaft reversegear; a reverseidler gear having constant mesh with' said countershaft reverse gear andadapted to be shifted into and out of'engagement with said driven gear;

shiftA means for shifting said reverse idler gear; a stationarilymounted idler shaft supporting said re-` verse idler gear for shiftingmovement therealong:

disposed in the path of gear-engaging shift of said reverse idler gearfor braking rotation of said reverse idler gear prior in engagementthereof with said driven gear.-

7. In a transmission having axially aligned driving and driven shafts; adriven gear mounted on said driven shaft; countershaft gearing drivinglyconnected to said driving shaft and coma friction surface non-rotatablyconnectedf ing surface; a synchronizer splined to said idler shaft for`displacement therealong, said synchronizer .having a conical' 'surfaceengageable with said gear conical surface in response 4to gear-engagingshift Aof said reverse idler gear; and means providing an axiallyyielding connection between said synchronizer and saididler shaft;

10. In a transmission according to claim 9 :said

reverse idler gear having a shoulder; said synchronizer having a slotadjacent said'shoulder; and a snap ring carried in said slot andengaging said shoulder whereby to releasably connect said synchronizerwith said reverse idler gear.

ll. In atransmission according to claim 9; said yreverse idler gearhaving a shoulder; said synchronizer having a slot adjacent saidshoulder; and a snap zing carried in said slot and engaging saidshoulder whereby to releasabiy connect said synchronizer with saidreverse idler gear;

'said synchronizer and shoulder having alignable openings therethroughdirected generally toward said snap ring for accommodating a tool todisengage said snap ring from said shoulder and thereby' facilitateremoval of said synchronizer from said reverse idler gear.

i 12. in a transmission having axially -aligned driving anddrivenshafts;l driving and driven gears, said driving gear being shiftableinto and out of engagement with said driven gear. said driven gear beingmounted on and having a constant drive connection with the driven shaft;

countershaft gearing, including a countershait.

' reverse gear, drivingly connected with the driving shaft; shift meansoperable to shift said driving prising a countershaft reverse gear; areverse idler gear having constant mesh with said countershaft reversegear and adapted to be shifted into and out of engagement with saiddriven gear; shift means for shifting said reverse idler gear; astationarily mounted idler shaft supporting said reverseddler gear forshifting movement therealon'g; a friction braking lsurface; means naxially yielding connection between said surface and said idler shaft,said surface bedisposed in the path of gear-engaging shift of saidreverse idler gear.

gear towardand from engagement with said driven gear thereby, to.provide a. reverse drive from said driving shaft to said driven shaftthrough said countershaft reverse gear and said driving and drivengears; and means operable in response to gear-engaging operation 'ofsaid shift means for braking rotation of said countershaft reverse4 gearprior to engagement of said driving and driven gears; said driving gearhav-l .ing constant mesh with said countershaft reverse gear; saidbraking means comprising a nrst friction surface rotating with saiddriving gear,4 and a statlonarily mounted second friction sifrf adaptedfor engagement with said rst surface. 13. In a transmission havingaxially aligned driving and driven shafts, a countershaft-driven gearset adapted to receive drive from said driving shaft for driving saiddriven shaft reversely with respect to said driving shaft, said gear setincluding, as a component gear element, a. driveprising relativelydisplaceable and relatively` en- Y gageable friction surfaces one havingdrive connection with said drive-control gear and the other beingstationarily rnounted rotatably, said friction surfaces` being soconstructed and arranged that displacement of one of said surfacesrelative to and toward the other is' effected in response to shift ofsaid drive-control gear from its said flrst position toits said secondposition thereby to rela- 10 tively engage said surfaces.

OTTO E. FISHBURN.

